The blue crab, Callinectes sapidus, represents an ecologically and economically important component of marine and estuarine ecosystems. In Florida, blue crab landings accounted for $9.6 million dollars during the 2010 fishing season. Accurate stock assessments for this valuable fishery are essential. Age is a critical biological component of accurate stock assessments; however, blue crabs and other crustaceans are especially difficult to age because of the complex nature of discrete growth. Biochemical extraction of an aging pigment, lipofuscin, was developed using blue crab eyestalks. The current study investigated the effects of freezing preservation on lipofuscin extracts and examined whether the extraction methodology, developed by Chesapeake Bay researchers, was useful for aging Tampa Bay blue crabs populations. Significant differences in lipofuscin index were found between samples frozen (2 weeks at -80°C) prior to analysis and those processed and assayed immediately (p < 0.001). Quarterly assays of the cohort of known-age individuals revealed a negative linear trend (y = -0.12x + 0.49, p < 0.001) in lipofuscin index over a 12-month period. This result suggests that extraction of lipofuscin is not appropriate for age determination of Florida blue crabs. Investigations into possible causes of the negative trend in lipofuscin suggest this method deserves further examination and refinement before it is acceptable as a reliable method for age determination in Florida blue crabs. Growth data of the known-age population collected during this study revealed that blue crabs in Tampa Bay can reach exploitable size in under sixth months and female crabs can reach sexual maturity within seven months of hatching. These growth patterns have the potential to enhance future Florida stock assessments.

Made available in DSpace on 2016-06-02T19:29:02Z (GMT). No. of bitstreams: 1 TeseNFOM.pdf: 709494 bytes, checksum: 789afd3e9ac18ee02e65bd17427b2035 (MD5) Previous issue date: 2006-06-06 / With aim to know the community structure of the Crustacea Brachyura and analyze the trophic dynamics of the species Callinectes dane, C. larvatus e C. ornatus in the seagrass bed of Halodule wrightii Aschers, studies were carried out during a dry period (February, 2001 and September to December, 2001) and the wet period (March to August, 2001) in the Forno da Cal beach, Itamaraca Island, Pernambuco, Brazil. The sampling method adopted was nocturnal trawling on the seagrass using a small (2m width) bottom net with internal mesh of 5mm and external of 2mm. Additional samplings were carried out on a period of 24 hours, in February, May, July, September and December, 2001. Samplings were also carried out on the adjacent sandy flat without vegetation, in March, June, August and December, having as objective to compare the biomass, abundance and diversity of this habitat with the seagrass in this same period. To determinate the gastric evacuation rate in the Callinectes sp., experiment was carried out. The results indicate that the Portunidae family contributed with 93% of the total captures. The species Callinectes ornatus, C. danae, C. larvatus and Portunus ordwayi were the most frequent. The highest density occurred in March, positively correlating with the air temperature, and the highest biomass was observed in July, with a positive correlation to density of cast algae. The seagrass presented the highest averages of densities, biomass, number of species, richness and diversity when compared to the adjacent sandy flat. Even if the number of species observed in the sand is higher, these presented well-distributed in the environment, with equitability value higher than in the seagrass. Animal organic matter, Gastropoda and Macrophyta were the food items that most contributed in the analysis of the stomach content of the species C. danae, C. larvatus and C. ornatus. It was observed that the smallest organisms have fed of small preys and with low mobility, as in the case of highest consume of Polychaeta, Copepoda and Amphipoda by specimens of smaller carapace width. Two feeding rhythms were observed for Callinectes: a diurnal one from 4:00 to 9:00 am and a nocturnal one between 21:00 and 22:00 pm. The evacuation rate (E) obtained by the regression analysis was E = 33.26% VE h-1. The daily ration in the sampled months in the 24-hour analyses was of 798.24% SV (the stomach fullness). After transforming the stomach fullness to somatic weight a day, the observed value was 20.748%.d-1. Then, C. ornatus with weigh of 1 g may consume 0.207 g food/ day. The seagrass bed represented as an important food source to Brachyura s population, due to the diversity of preys and refuge area, not only by the vegetation of seagrass but also by the abundance of cast algae, especially for the species Callinectes danae, C. larvatus and C. ornatus. / Com objetivo de conhecer a estrutura da comunidade de Crustacea Brachyura e analisar a dinâmica trófica das espécies Callinectes dane, C. larvatus e C. ornatus no ecossistema de prado de capim marinho Halodule wrightii Aschers foram realizados estudos durante o período seco (fevereiro/2001 e setembro a dezembro/2001) e chuvoso (março a agosto/2001) na praia de Forno da Cal, Ilha de Itamaracá, Pernambuco, Brasil. O método de amostragem foi através de arrastos noturnos sobre o prado marinho com uma draga leve retangular com rede interna de malha de 5mm e externa de 2mm de abertura. Coletas adicionais, no período de 24 horas, foram realizadas em fevereiro, maio, julho, setembro e dezembro de 2001. Em março, junho, agosto e dezembro foram efetuadas também coletas na planície de areia adjacente sem vegetação com o objetivo de comparar a biomassa, abundância e diversidade com o habitat de prado, nesse mesmo período. Para determinação da taxa de evacuação gástrica em Callinectes sp. foi realizado um experimento. Os resultados indicam que a família Portunidae contribuiu com 93% do total de capturas. As espécies Callinectes ornatus, C. danae, C. larvatus e Portunus ordwayi foram as mais freqüentes. A maior densidade de braquiúro foi registrada em março, correlacionando-se positivamente com a temperatura do ar, e a maior biomassa em julho, com uma correlação positiva com a densidade de algas arribadas. O ambiente de prado apresentou as maiores médias de densidade, biomassa, número de espécies, riqueza e diversidade quando comparado a uma planície de areia adjacente. Embora o número de espécies encontradas na areia seja menor, estas se apresentaram bem distribuídas no ambiente, com valor de equitabilidade maior que nos prados. Na análise do conteúdo estomacal de C. danae, C. larvatus e C. ornatus os itens alimentares de maior contribuição foram Matéria Orgânica Animal, Gastropoda e Macrofita. Foi observado que os menores organismos se alimentaram de presas pequenas e de pouca mobilidade, como foi o caso do maior consumo de Polychaeta, Copepoda e Amphipoda por espécimes de menor largura da carapaça. Dois ritmos alimentares foram observados para Callinectes: um diurno das 4:00 ás 9:00 horas e outro noturno entre 21:00 e 22:00 horas. A taxa de evacuação (E) obtida através da análise de regressão linear foi E = 33,26% VE h-1. A ração diária para o total dos meses amostrados nas análises de 24 horas foi de 798,24% SV (volume estomacal máximo). Depois de transformado o volume estomacal máximo para peso somático por dia o valor encontrado foi de 20,748%.d-1 peso somático. Assim, C. ornatus com peso de 1 g consumiria 0,207 g por dia de alimento. Além de área de berçário, visto a captura de assentantes e juvenis, o prado de capim marinho é uma importante fonte de alimentação para a população de Brachyura, por causa da diversidade de presas, e área de refugio, não só pela própria vegetação, mas também pela abundância de algas arribadas, principalmente para as espécies de Callinectes danae, C. larvatus e C. ornatus.

Made available in DSpace on 2014-06-12T22:57:35Z (GMT). No. of bitstreams: 2 arquivo1333_1.pdf: 727183 bytes, checksum: e370d1619a847ea6e2834f8c66cea7d2 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Nas regiões tropicais e subtropicais destacam-se os manguezais por apresentarem condições favoráveis para alimentação, proteção e reprodução de diversas espécies de animais. O complexo estuarino do Canal de Santa Cruz merece atenção por sua alta produtividade e por apresentar uma atividade pesqueira intensa. Neste contexto, o siri Callinectes danae Smith, 1869 possui importante papel na dinâmica trófica desses ecossistemas, atuando principalmente como necrófagos e ativos predadores. Nesse intere, o presente trabalho teve por objetivo promover o estudo qualitativo e quantitativo da fauna bêntica do infralitoral e conhecer a alimentação natural de C. danae nos estuários dos Rios Botafogo e Carrapicho através da análise do conteúdo estomacal. Como definido pelo Instituto Milênio Uso e recursos da zona costeira , foi definido o Rio Botafogo como área experimental e o Rio Carrapicho como área controle. Ao longo de cada rio foram demarcadas quatro estações, nas quais foram realizadas coletas diurnas nos meses de agosto e outubro de 2003, janeiro, fevereiro, junho e agosto de 2004, através de arrastos com rede de porta com saco em malha de 5mm, com duração de 15 minutos. Em campo as amostras foram etiquetadas, acondicionadas em sacos plásticos e mantidas em caixa térmica com gelo. Foram anotados dados de profundidade, salinidade e temperatura da água de cada estação de coleta. No Laboratório de Carcinologia - DOCEAN/UFPE os organismos foram triados, identificados sob estereomicroscópio com auxílio de literatura pertinente, contados e mantidos em potes plásticos com álcool a 75%. Foram identificados sete grupos taxonômicos: Sipuncula, Porifera, Polychaeta, Mollusca, Echinodermata, Crustacea e Chordata; e 51 espécies, com duas novas ocorrências para as áreas estudadas (Charybdis hellerii e Paguristes triangulopsis). Destas, o Rio Botafogo apresentou 31 espécies em 8055 indivíduos, dos quais 70,9% são Mollusca, 27,6% Crustacea e 1,5% Echinodermata. Enquanto o Rio Carrapicho apresentou 47 espécies de um total de 1.013 indivíduos dos quais 62,2% são Crustacea, 20,5% Echinodermata, 9,2% Mollusca e 8,1% Polychaeta. Os demais grupos taxonômicos não foram utilizados nas análises estatísticas e o Rio Botafogo não apresentou organismos do grupo Polychaeta. Anomalocardia brasiliana foi a espécie mais abundante e dominante no Rio Botafogo e C. danae no Rio Carrapicho. As espécies da fauna bêntica apresentaram maiores valores de freqüência de ocorrência e abundância durante o período seco para as áreas estudadas. Separadamente os C. danae foram sexados e aferidos peso e largura da carapaça. Posteriormente os estômagos foram retirados, pesados e estimado o grau de repleção estomacal. Também sob estereomicroscópio e literatura pertinente os itens alimentares foram identificados e aplicada a metodologia de pontos. Foram identificados 9 itens na alimentação natural de C. danae nos rios estudados, Algae, Macrophyta, Foraminiferida, Mollusca, Polychaeta, Crustacea, Echinodermata, Teleostei e MOA (Matéria Orgânica Animal). MOA, Mollusca e Crustacea foram os itens mais freqüentes encontrados. Na análise da alimentação de machos e fêmeas não se verificou diferenças na preferência alimentar. Nas áreas estudadas Mollusca foi o item de maior contribuição durante o período seco e MOA no período chuvoso. No Rio Botafogo, as categorias adulto e jovem apresentaram diferenças na preferência alimentar durante o período seco, Mollusca e MOA, respectivamente, e semelhantes no período chuvoso, MOA para ambas as categorias. Já no Rio Carrapicho os resultados foram semelhantes, uma vez que as categorias adulto e jovem consumiram preferencialmente Mollusca no período seco e Crustacea no período chuvoso. Portanto, C. danae é uma espécie de hábito alimentar oportunista e sua preferência alimentar pode refletir a quantidade de suas presas no ambiente, uma vez que seus itens preferenciais corresponderam ao grupo das espécies mais abundantes neste trabalho

No description available.

The Food and Drug Administration has recently expressed concern for the safety of seafood and seafood products. One of the concerns is the presence of Bacillus cereus in fresh blue crab meat. Bacillus cereus is a spore-forming pathogen whose spores survive the customary thermal treatments applied during cooking and pasteurization; therefore it could potentially present a health concern to consumers as the microorganism could increase to pathogenic levels. The objectives of this study were to evaluate the effects of a post-processing method i.e. high hydrostatic pressure treatment on the quality of fresh crab meat and to evaluate the effectiveness of high pressures on the inactivation of B. cereus spores. Fresh blue crab meat was pressurized at 300 and 550 MPa at 25° C for 5 min and stored at 4° C for 31 days to determine the pressurization effects on the microbiological, physical, and sensory quality of the meat. A pressure of 300 MPa caused a 1 log reduction in total aerobic plate count and a 3 day lag period, whereas 550 MPa inactivated 2 logs in total aerobic plate count with no evident lag phase. Physical and sensory qualities of pressurized crab meat were not statistically different from the untreated crab meat (P>0.05). A pressure of 300 MPa extended the shelf-life from 17 to over 24 days with the prevalence of Carnobacterium piscicola at the time of spoilage. Crab meat treated with 550 MPa was not rejected by sensory panels at day 31 and Enterococcus spp. was identified as the predominant microorganism. High hydrostatic pressure (550 MPa at 40° C for 15 min) inactivated less than 1 log (0.66 log) of B. cereus spores inoculated in fresh crab meat. The meat essentially had a protective effect on pressure inactivation of the spores. During storage (31 days), surviving B. cereus was suppressed and outgrown by the other pressure resistant microflora at a storage temperature of 12° C. At 4° C, B. cereus could compete with the other pressure-resistant microflora and was isolated even at the end of the storage period (day 31); however, diarrheal toxin was not detected in any stored samples. / Ph. D.

The dehydration rates of crabs during low temperature storage and various cooking processes were determined. Season, cooking time, and cooking method significantly affected the weight loss of crabs. The thermal energy (F250 ) crabs received during a commercial cooking process was evaluated by season, cooking method and time, and crab type. The effects of sex, size, and type (sexual maturity) of crab and season on the yields of lump, top flake, bottom flake, and claw and total meat were examined. The effects of cooking time and method and storage time on meat yield was also determined. During summer, male crabs yielded more lump, claw, and total meat than female crabs, and clean female crabs yielded more lump, top flake, and total meat than sponge female crabs when retort cooked for 10 minutes. / Ph. D.

In recent years, the blue crab fishery has become the main source of income for Virginia's watermen. This fact, along with growing concerns of overharvesting and uncertainty about the amount of effort in the fishery, has led to calls for more complete data on the fishery. This study examined the characteristics of Virginia's blue crab fishery, through an extensive survey of crab pot license holders conducted on a monthly basis from March to November of 1992. Along with a description of the people in the fishery, this study also modeled prices, harvest levels, and income levels for the blue crab industry. Because the models were interactive in nature, the effects of various fishery management strategies were also analyzed. The main emphasis of the policy simulations was to discover what impacts the different strategies had on harvest and income levels. The results of the simulations showed that many of the policies currently under consideration will have only a small impact on overall harvest and income levels, but there are some larger distributional effects among different firm classes. The findings of this study suggest that in order to gather accurate and useful data on the fishery, the random surveying techniques of this study should be continued over a period of years. / Master of Science

The present research examined respiratory responses of blue crabs to long term (4, 13, and 21 days) hypercapnic hypoxia in freshwater at 23 C. Hypoxic conditions (50-60 & 75-85 mmHg O2) were induced by allowing the crabs to consume their oxygen supply, resulting in a hypercapnic induced decrease in pH that remained through the exposure. Postbranchial hemolymph responses to hypoxia/hypercapnia in freshwater demonstrate decreases in PO2, increases in PCO2, and decreases in pH. Lactate levels decreased over time, but hemocyanin concentration was highly variable with no trends. PH, lactate, and hemocyanin observations also demonstrated high variability and a variety of different responses in individual crabs. There was no evidence of improving oxygen transport abilities. Despite varying responses high mortality rates were observed. The high mortality rate suggests blue crabs are not able to survive the multiple stress of hypoxia/hypercapnia along with the stress of living in freshwater. The mortality rates observed are much greater than previous blue crab hypoxic studies in saltwater. Elevated mortality may result from a failure of oxygen transport, acid-base balance or ion regulation.

Blue crabs are a widely distributed estuarine species with broad economic and ecological importance. Several studies have linked blue crabs to freshwater inflows, but the precise nature of this link is still uncertain, as blue crabs have a complex life cycle that utilizes both marine and estuarine environments. One potential link between blue crabs and freshwater inflows is during recruitment, when megalopae developing offshore return to estuaries before molting into juvenile crabs. Megalopae swim during the flood tide to ensure delivery into and farther up estuaries. The behaviors regulating selective tidal stream transport (STST) on the flood tide were originally studied in North Carolina in an estuary with regular freshwater inflows and a strong salinity gradient. The model of STST was re-examined in the Mission-Aransas, an estuary with episodic freshwater inflows and salinity gradients ranging from normal estuarine conditions to hypersaline during droughts. The behavioral responses of megalopae to a range of rates of salinity increase were tested, and then modeled onto rates of salinity change observed in the field to determine the theoretical ecological consequences of STST for blue crab populations in the Mission-Aransas Estuary. To validate the ecological trends predicted by the behavioral model of STST, a simple, long-term data set reflecting changes in megalopae abundance is needed. Hog’s hair collectors are a simple and widely used method of quantifying abundance of brachyuran megalopae, including blue crabs. However, the efficiency of hog’s hair collectors in sampling for megalopae is unknown. Several studies have reported poor correlations between settlement on hog’s hair collectors, transport, and abundance of megalopae in the plankton due to disparate temporal scales and potentially turbulence-driven decoupling. Each of these issues were addressed in field and flume experiments, which were used to develop a model for interpreting settlement on hog’s hair collectors in terms of transport and planktonic abundance. / text

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2006. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-11-19T11:17:25Z No. of bitstreams: 1 Dissertacao Marcos.pdf: 1118373 bytes, checksum: 7a93dd33316a5f05afa5bd7d2f611436 (MD5) / Approved for entry into archive by Angelica Miranda (angelicacdm@gmail.com) on 2013-11-20T21:49:31Z (GMT) No. of bitstreams: 1 Dissertacao Marcos.pdf: 1118373 bytes, checksum: 7a93dd33316a5f05afa5bd7d2f611436 (MD5) / Made available in DSpace on 2013-11-20T21:49:31Z (GMT). No. of bitstreams: 1 Dissertacao Marcos.pdf: 1118373 bytes, checksum: 7a93dd33316a5f05afa5bd7d2f611436 (MD5) Previous issue date: 2006 / Devido à falta de estruturas rígidas para determinação de idade em crustáceos, métodos que se baseiam na determinação de idade através de freqüência de tamanhos são comumente utilizados. Neste trabalho, foram estudados aspectos do crescimento em laboratório e no ambiente, de juvenis e adultos, do siri-azul Callinectes sapidus, com o objetivo de desenvolver uma metodologia adequada à obtenção do siri-mole (softcrab) no estuário da Lagoa dos Patos. Os indivíduos de laboratório foram coletados e acompanhados individualmente. A biometria foi realizada antes e depois das mudas. A temperatura foi mantida constante (25±2°C) e a salinidade foi mantida a 20±5. Os indivíduos do ambiente foram coletados entre 2002 e 2003 em pontos prédeterminados no estuário da Lagoa dos Patos, com rede de portas. A obtenção das curvas de crescimento se baseou nos modelos de Gompertz e Bertalanffy, neste último utilizou-se o método de determinação de idade através do acompanhamento do deslocamento modal. Foram utilizados aspectos biológicos conhecidos da espécie para validar as curvas de crescimento. O tamanho máximo de largura de carapaça utilizado foi mantido fixo em todas as análises (157,78 para fêmeas e 162,71 para machos). A curva de Gompertz foi aplicada aos indivíduos menores cultivados em laboratório e os parâmetros obtidos foram k=0,0238/dia; co=4,15; longevidade de 2530 dias para machos e k=0,00375/dia; co=4,69; longevidade de 1638 dias para fêmeas. A curva de Bertalanffy foi determinada através da análise de progressão modal. Para os maiores indivíduos cultivados em laboratório os parâmetros e a longevidade obtidos foram k=0,0016/dia; to=-0,7; longevidade de 3117 dias para machos e k=0,0018/dia; to=-12,6; longevidade de 2795 dias para fêmeas. Os parâmetros de crescimento e a longevidade estimados para os animais coletados no ambiente foram k=0,04502/dia; to=-4,23; 1267 dias para machos e k=0,04271/dia; to=-3,71; 1260 dias para fêmeas. Os animais de laboratório exibiram crescimento diferente dos animais do ambiente, as estimativas mostram os siris crescendo menos e tendo longevidades maiores. O sistema de cultivo utilizado para a manutenção dos animais em laboratório mostrou-se eficiente. A obtenção do siri-mole poderá ser uma fonte alternativa de renda para os pescadores artesanais. / The absence of hard structures capable of register age on crustacean, requires the use of methods such as modal progression analysis (MPA) to estimate growth. In this paper, growth and mortality of juveniles and adults of the blue crab Callinectes sapidus were studied through field and laboratory surveys, in attempt to develop an adequate method to obtain softcrabs on the Patos Lagoon estuary. Gompertz and von Bertalanffy curves were used to estimate growth parameters of blue crabs collected on the Patos Lagoon estuary. Crabs obtained from field sampling were kept under laboratory conditions (temperature = 25±2°C, and salinity = 20±5), on a water recirculating system and measured before and after molting. Individuals used for growth and mortality analysis were collected between 2002 and 2003 in predetermined sampling sites by using otter-trawl and renfro nets. Measures consisted of carapace length, taken from the last antherolateral spines (CL in millimeters) and wet weight (W in grams). Maximum carapace lengths used as asymptotic length were taken from long term catch series of larger individuals and used to validate the growth curves (157.78 mm for females and 162.71 mm for males). Growth estimates based on Gompertz model for smaller individuals reared in laboratory, were as follows: k=0.0238; co=4.15; longevity= 2530 days for males and k=0.00375; co=4.69; longevity= 1638 days for females. Growth estimates based on von Bertalanffy growth curve were k=0.0016/day; to=-0.7; longevity= 3117 days for males and k=0.0018/day; to=-12.6; longevity= 2795 days for females. Growth parameters and longevity estimates for the field collected animals were k=0.04502/day; to=-4.23; 1267 days for males and k=0.04271/day; to=-3.71; 1260 days for females. No significant correlation was obtained among laboratory and field animals, suggesting a different growth rate. The Patos Lagoon estuary shows good potential for the establishment of a softcrab facility, as an alternative income for the artisanal fisheries.